Abstract: A method of testing a system including a plurality of modules, each of which in use, produces from an air supply, a product gas which is one of oxygen gas and oxygen enriched gas, the method including providing to an inlet to at least one of the modules, when the module is not in use, a restricted air supply, and at an outlet of the module, sensing at least one of the oxygen concentration and product gas pressure, and analysing the sensed oxygen concentration and/or product gas pressure during a test period to determine the potential performance of the module in use.

Abstract: A combination of a rotor and a stator assembly, the stator assembly having a first part and a second part, the first and second parts being generally concentric, the rotor being rotatably mounted in the stator assembly, the combination further including a plurality of elongate resilient damping elements which extend generally in an axial direction, and being located between and spacing apart the first part and the second part of the stator assembly.

Abstract: A gas generating system for generating a supply of oxygen or at least an oxygen rich gas, and a residual gas, the system including a first gas separation device for separating from a supply gas, a first gas being oxygen enriched gas, to leave a residual gas. The first oxygen enriched gas from the first gas separation device is communicated to a second gas separation device for further separating from the first oxygen enriched gas, oxygen gas. The second gas separation device generating a product gas which is at least highly oxygen enriched and a further residual gas, with at least one of the first and second gas separating devices including a ceramic membrane through which in use gas ions diffuse.

Abstract: A valve assembly including an actuator and a valve, the valve including a valve body having first and second ports and a valve seat between the first and second ports, a valve member carried on a valve stem and the valve stem being moveable to move the valve member at least one of into or out of engagement with the valve seat to prevent or permit communication between the first and second ports and wherein the actuator includes a stepper motor the rotational movement of which is converted to linear movement of the valve stem by a transmission, the transmission being adapted to maintain the valve stem in a position to which it is moved by the operation of the actuator whereby the transmission means is a non back-derivable transmission.

Abstract: A mechanical hand has a rigid enclosure for housing the hand of a user, and at least one pair of gripping elements are provided on the rigid hand enclosure. One of these gripping elements is pivotally attached to the enclosure so as to be capable of movement towards and away from the other gripping element. Movement of the movable gripping element, at least towards the other gripping element, is provided by an hydraulic actuator arrangement that includes fluid pressure control means responsive to a manually movable member housed within the rigid hand enclosure. The arrangement is such that a force applied to the manually movable member by the hand of a user effects rapid movement of the pivotal gripping element until an object is being held between the pair of gripping elements, at which time the force applied to the manually movable member is translated into a force that is applied through the pivotal gripping element to exert a firm grip on the object.

Abstract: An air cycle air conditioning system has an air expansion turbine arranged to deliver air through an outlet formed by a wall having an outer surface that defines in part passage means through which supply air flows to the turbine. Heat flow from the supply air into the wall prevents formation of ice in the outlet so that in at least one phase of system operation the turbine delivers air at sub-zero temperature with which large quantities of augmenting air can be mixed so as to increase the system cooling capacity.